Presently, organic ElectroLuminescence (EL) devices are being developed as candidates for next-generation display technology. An organic EL element is a light emitting element, luminescent components of which emit light evenly in all directions. Therefore, some components emitting light within a Light Emitting Layer (EML) are completely reflected due to a difference in refractive index between an organic layer and air, and the light is guided within the element and is not extracted to the outside.
For example, when a refractive index of the light emitting layer is 1.8, approximately 20% of luminescent components are extracted vertically, but approximately 80% of the luminescent components are sealed between a reflective layer 3 (AL) and an air layer. When the refractive index of the light emitting layer differs from a refractive index of air, the luminescent components become sealed within a layer between the reflective layer 3 and the air layer according to the principle of refraction.
PTL 1 describes a planar display device including a light reflective layer configured to reflect light discharged to a support substrate side. The light reflective layer includes a plurality of recessed portions as incident angle adjustment parts disposed at a distance from a plurality of display elements with an insulating layer having optical transparency interposed between the display elements and the recessed portions to orient each beam of reflected light toward the corresponding display element, and each recessed portion includes an inclined face along an outer edge of an organic light emitting layer of the corresponding display element.